As the investigation for Friday’s fiery and deadly plane crash on Interstate 75 near Naples continues today, people around Southwest Florida may be wondering what is happening at the crash site at mile marker 106.8 just north of exit 105 (Golden Gate Parkway).

The I-75 southbound lanes near the crash site remained closed on Sunday as investigators from the National Transportation Safety Board analyzed the site and what remained of the Bombardier 600 dual engine jet that crash landed just after 3 p.m. on Feb. 9. The pilot and co-pilot were killed. Three people on the jet survived.

Initially, it was expected the southbound lanes would be closed for 24 hours.

What to know: NTSB investigation

According to the NTSB website, “while the exact scope and extent of any specific investigation depends on the nature of the accident being investigated, every NTSB investigation goes through the same general process.”

What is the ‘process’ at an NTSB investigation?

• the initial notification and decision to investigate
• on-site fact gathering
• analysis of facts and determination of probable cause
• acceptance of a final report
• advocating for the acceptance of safety recommendations arising from the investigation

NOTE: The NTSB says on its website that “this process is not strictly linear, and phases overlap. For example, investigators may be waiting for log books while they are analyzing weather information, or their analysis of engine performance data may prompt them to request additional information from the manufacturer.”

More: ‘Are they alive?’ Video shows Naples man rush to help victims of fiery plane crash

How long does the investigation take?

The NTSB says the timing between the beginning of an investigation and a probable cause determination and report varies based on the complexity of the investigation and the workload of the agency’s investigators. In general, the NTSB tries to complete an investigation within 12 to 24 months, but these and other factors can greatly affect that timing.

What is likely happening at the Naples plane crash scene?

• During this phase, NTSB investigators gather the data and information needed to analyze the accident and determine a probable cause. This includes when an NTSB investigator or investigative team – known as the Got Team – travels to the accident site, as well as time spent gathering additional information from outside of the accident scene itself, such as flight logs, maintenance records, and personal interviews.
• ​Something known as The Party System allows the NTSB to designate other organizations or companies as parties to the investigations – in this particular case with the Naples plane crash, the Florida Highway Patrol – and allows the Board to leverage its resources to investigate.

Did you know? NTSB annual investigations

The NTSB investigates about 1,200 aviation accidents and incidents a year, and about 60 accidents in the other modes of transportation: rail, highway, marine, and pipeline.  In some cases, NTSB decides to hold an investigative hearing  to assist with determining facts about the transportation accident.

What is the difference between an aviation accident and incident?

• An aviation accident is defined by the Convention on International Civil Aviation Annex 13 as an occurrence associated with the operation of an aircraft, which takes place from the time any person boards the aircraft with the intention of flight until all such persons have disembarked, and in which (a) a person is fatally or seriously injured, (b) the aircraft sustains significant damage or structural failure, or (c) the aircraft goes missing or becomes completely inaccessible.
• Annex 13 defines an aviation incident as an occurrence, other than an accident, associated with the operation of an aircraft that affects or could affect the safety of operation.